Magnetoresistive sensor with reduced parasitic capacitance, and method

Abstract

A magnetic-field sensor adapted to detect an external magnetic field, comprising: a first chip, including a first magnetoresistive structure for detection of the external magnetic field, the first magnetoresistive detection structure including an electrical-contact pad and magnetoresistive means; and a second chip housing an integrated electronic circuit and a magnetic-field generator, the first and second chips being mutually arranged in such a way that the integrated electronic circuit can be electrically coupled to the electrical-contact pad of the magnetoresistive structure and in such a way that the magnetic-field generator can be magnetically coupled to the magnetoresistive structure.

Description

BACKGROUND[0001]1. Technical Field[0002]The present disclosure relates to a magnetic-field sensor, in particular to a sensor that uses anisotropic magnetoresistive (AMR) elements in order to detect a magnetic field that is external to the sensor and acts on the sensor itself.[0003]2. Description of the Related Art[0004]Magnetic-field sensors, in particular AMR sensors based upon anisotropic magnetoresistance, are used in a plurality of applications and systems, for example in compasses, in systems for detection of ferromagnetic materials, in the detection of currents, and in a wide range of other applications, thanks to their capacity for detecting natural magnetic fields (for example, the Earth's magnetic fields) and magnetic fields generated by electrical components (such as electrical or electronic devices and lines traversed by electric current).[0005]The phenomenon of anisotropic magnetoresistivity occurs within particular ferromagnetic materials, which, when subjected to an ex...

AI Technical Summary

Problems solved by technology

This voltage Voff does not have any relationship with the magnetic field that is to be detected but adds, in an undesirable way, to the signal generated by the transduction of the magnetic field that is to be detected in voltage.

In addition, the process (which is relatively simple) of deposition of the ferromagnetic material, is rendered burdensome by numerous successive process steps to provide various metal levels, considerably increasing the manufacturing costs in terms of number of masks and process cost (machinery, process steps, manufacturing times).

In addition, given the presence of current peaks of a high value, there may arise problems due to the contacts, in particular on account of generation of parasitic signals (parasitic currents and voltages, parasitic capacitances, etc.), and / or problems of reliability of the contacts provided by means of bonding and / or using bumps, which can jeopardize proper operation of the sensor.

What has been said must consequently be taken into account in the design of the AMR sensor and in the analysis of the output signal Vout acquired from the latter by the acquisition circuitry, which causes an increase of the hardware and / or software complexity of the AMR sensor and / or of the circuitry for power supply and generation and acquisition of signals.

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